Immunity
by Kazziiee
Summary: Bellarke zombie AU. Clarke getting bitten was never in Bellamy's plans, but neither was reuniting six years later to find out the bite didn't kill her and he essentially left her for dead. (Becho and Clexa touched upon as plot devices.)
1. Chapter 1

Bellamy and Clarke had known each other for the best part of their lives. Clarke was in the same class as Octavia in middle school and the pair quickly warmed to each other. Clarke's mother was a highly established doctor who spent a lot of long gruelling hours at work, leaving Clarke to spend the majority of her childhood shacked up at Octavia's house with her and her brother Bellamy. The blonde and the freckled boy had never really paid much attention to each other until Clarke's senior year when Octavia had too much to drink at their prom and Clarke had no other choice but to call Bellamy. He drove them both back to the siblings house where they shared their first kiss in the midst of a heartfelt conversation. The beginning of a 5 year long relationship. A relationship that ended as a result of the chemical outbreak which caused half of the worlds population to turn into brain-dead monsters. A relationship that ended the day Clarke was bitten.

Clarke looked at her arm and then at Bellamy. The vow they made long ago was lingering at the back of both their minds as they sat in an uncomfortable silence.

~four months into the apocalypse~

"If either of us get bitten we have to swear to shoot each other in the head," Clarke stated, blissfully unaware of the situation they would be in a year later.

"Okay, I promise," he replies, rolling his eyes, believing that the conditions would never prove themselves necessary.

They interlock their pinkies and seal it with a kiss. They had foolishly believed that the apocalypse was at its worst. That things could only get better. They had tricked themselves into believing that as long as they were together everything would be okay. The thing with possibilities, however, was that after the initial outbreak, the world seemed to be full of them and the only thing that truly kept them going was their motivated denial.

A year and a half had passed since they had made that promise. Their lives were riddled in loss after loss. Death after death. Grievance after grievance. They had watched the world around them disintegrate right in front of them; the only constant in their ever-changing lives had been each other. Despite their small shred of hope decreasing as each day passed, the challenges they faced only seemed to bring them closer and make their love even stronger.

They had been living alone in an underground bunker for the past four weeks. They'd only leave to find food or herbal remedies. Even then their expeditions would be no longer than an hour. This had changed when Bellamy had gotten the flu. A case Clarke had seen multiple times before at the hospital her mother worked at. A case that was a whole lot more serious in the midst of a zombie apocalypse.

"Stay here," Clarke urged whilst inspecting Bellamy's fever.

"What why? Where are you going?" Bellamy croaked out, prominent worry in his voice despite his illness.

"I'm just going to try and find some herbs. Your fever isn't getting any better and we've already been here way too long. We have to keep moving and we're not going to do that whilst you're like this," Clarke consoles, stroking a stray of Bellamy's curls away from his eyes.

Bellamy failed to understand that to Clarke, he was always worth the risk. She would give her entire life for him, a statement that had been true before the apocalypse had even began.  
"Please don't le-"

"Bell, I'm going to be fine, okay? We're never going to survive if you're in this state. Just trust me."

And he did. It was arguably the only thing he was good at.

Several hours had passed. Despite the complete and unadulterated trust he had for Clarke, Bellamy knew that the apocalypse was unpredictable. They were never truly safe. Especially when they weren't together. He wasn't entirely sure what 'home' meant these days. But home felt a lot like her. And his home had just come busting in the door, blood dripping from her arm.

"Bellamy, I-" Clarke started, through staggered breaths.

"Clarke please don't say it..."

Bellamy could see the bite marks. But still, ignorance is bliss and he wanted to live in bliss just a little while longer.

"I've been bitten..."

Bellamy looked at the bunkers ceiling, caught in a daze. He and Clarke had become two halves of a whole. They had survived this long because they complete each other in every sense of the phrase. Life without her was unimaginable. He had convinced himself for the longest time that they were soul magnets, destined to spend eternity surrounded by each others energy. But now that death was staring at them, all of their midnight promises and unfinished plans became completely unattainable. They would not survive the apocalypse, and they would not see the day that zombies are eradicated. At least not together like they had dreamed of to keep them going through their darkest days.

"Bellamy... please look at me," Clarke begged, tears falling.

He slowly raised his gaze to meet hers. She reaches down to take the revolver from his belt, handing it over to him, gripping his hands between hers as she places a kiss to his lips. He was frozen in complete shock as he stared at her. The innocence of her face reminded Bellamy of the first day they met, Clarke's blonde ringlets cascading down her face from the tight ponytail her mother had clearly fashioned for her. Nine years had passed and she was still the same beautiful princess, only now she was tainted with grief and littered in battle wounds. He still loved her like she was the sun in his sky in a world that couldn't function in darkness. Life without Clarke wouldn't be life. It would be survival. It would be living simply for the sake of being alive. He didn't want that. He wanted her.

"Find Octavia, or a group or just find some shelter. You know how to survive. You have a big heart, Bellamy. Just be careful who you give it to, don't trust everyone. We've seen firsthand what misplaced trust leads to," Clarke chokes out, hands gripping his as they press their foreheads together.

"Clarke... I can't..." he responds, his lips trembling with unease. "I can't survive without you... I don't want to!"

~5 years pre-apocalypse~  
Bellamy woke up at 12am to hear his phone buzz on his bedside table. Clarke Griffin is calling. Bellamy frowned. The only time Clarke ever called Bellamy was when Octavia's phone was dead and they wanted some money for food.

"Yes, O?" He answered groggily.

Although his little sisters late night calls from Clarke's phone were unwanted and annoying, he still cared about both of them and he was a sucker when it came to Octavia and her pleas.

"Um... no, actually. It's Clarke."

"Oh, right... sorry, I just assu-"

"Yeah, no it's cool. I get it," Clarke stated, her words slurring slightly from the standard intoxication that senior prom brings. "Um, so this is kind of awkward. Octavia has passed out in the girls toilets and we were gonna get an Uber from her account but I can't find her phone anywhere and if my mum saw me or Octavia in this state she'd completely flip out and-"

"I'm on my way," Bellamy said abruptly, interrupting her drunken babbles.

"Thank you so much, Bellamy. I owe you one."

Their ride home was comfortable. Not lively or entertaining or anything interesting, but not awkward or uneasy either. When they arrived home they both helped getting Octavia cleaned up and tucked into bed.

"How is it already 5am?" Bellamy thought aloud, looking at the clock that was displayed on the wall.

"Well, at least you know that Octavia is good at not letting people take her clothes off when she's drunk because that was a hell of a handful," Clarke mused, opening the Blakes' fridge and grabbing out some orange juice.

"Help yourself, princess," Bellamy stated sarcastically.

"I always do!"

Bellamy chuckled in response to a wink from Clarke and went to the living room to sit down. He had class in a few hours and couldn't see the point in going back to sleep.

"I'm not very tired yet, mind if I hang out with you?"

"Go for it, I'm just gonna wait until my class starts anyway."

Three hours passed and their conversation had gone from talk about Bellamy's history major to Clarke's dreams of being a doctor, to Octavia's irrational fear of Mr Wiggles as a kid and even as far as Bellamy's 6 month relationship with an older woman. The time ticked by unnoticed and the pair quickly realised they had a lot more in common than they thought. They had practically sworn each other off with Clarke being Octavia's best friend and all, but after three hours of getting to know each other on a deeper level it was clear that they had an undeniable connection. It was only fitting considering the connection Clarke and Octavia had themselves.  
"You wanna know a secret?" Clarke said interrupting the flow of conversation with a flirty smile on her face.

"What's that?" Bellamy grinned, smelling the slight hint of whiskey on her breath.

"I've always thought you were like so ridiculously gorgeous. Like a Greek god or something. You're just like perfect, it's kind of unfair. I guess it must be a Blake thing."

Bellamy looked down, smiling from ear to ear. He was used to compliments, but coming from his sisters best friend who he'd secretly had a guilty pleasure for ever since she became of age, sent him into overdrive.

"That was a pretty good secret. Can I tell you one?"

Clarke nodded, biting her lip, eyes fixated on his as they edge closer together ever so slowly.

"I think that my sisters best friend is the most beautiful girl I've ever seen."

With that, Clarke closed the space between them, locking her lips with his. He snaked his arm around her hips, pulling her close to him as she moved her hand up to his cheek. They both pulled away gasping for air, keeping their foreheads touching as they stared at each other.

"I was talking about Raven, by the way," Bellamy joked, earning a chuckle and a playful slap from Clarke.

Bellamy would give anything to return to that moment right now. To live for 5 minutes in a world where the only threat was the arrival of a new day, the sun coming up and the birds tweeting, interrupting their meaningful thoughts.

"You need to do this. For me. For us."

Clarke pulls away, leaving the gun in his hand. He took a deep breath. He knew the severity of their promise and he knew that it was the right thing to do. But after two years of living a morally-corrupt lifestyle he wondered if there was such thing as 'right' and 'wrong.' However, he did know one thing for sure. He didn't want her to turn into one of the monsters out there. She deserved better.

He pulls the revolver up to her temple, tears falling so rapidly that he can barely see through them. He pulled off the safety trigger as Clarke closed her eyes.

"I love you, Bellamy Blake. May we meet again."

Bellamy's hand shakes furiously, he's completely blind to his surroundings now, unsure whether it's the tears or the sickness, or maybe just the pure horror of the situation. His finger just won't fucking move. He's pulled the trigger of this gun more times than he can count but killing her would blow up his entire world and shatter into a million pieces. Life just wasn't worth it without her.

"I can't do it... I can't just kill you, Clarke I can't. You deserved more than this. You can't just... die. You can't! I won't let you die alone."

"Bellamy, listen to me. You are going to survive this. You are going to fall in love again when the world is brighter and life seems reachable. You're going to see the new world order and have a family and achieve all of the goals we set together."

"The goals were set for us! Those plans are just empty unfulfilled promises without you. I'm nothing without you," Bellamy shouts, not out of anger but frustration and exhaustion.

The world after the apocalypse seemed pointless if she wasn't there to share it with him. He'd spend the rest of his life knee-deep in zombies if it meant that she was by his side.

He pulls her close, his grip tightening as he nuzzles into her neck. He whispers, "I can't lose you."

She pulls away from him, wiping her tears whilst gaining a facade of strength.

"Go. I'll do it."

"Clarke-"

"Please, Bellamy! Survive for me. Don't let me die in vain."

And with one last, starving kiss, Bellamy silently vowed to never let her down again. And for the next 6 years, he would spend every waking moment ensuring he never broke that promise. Every decision he made, every friendship he formed, every significant thing that happened in the years following were developed around the thought that Clarke was dead and it was his job to avenge her death by seeing the apocalypse through to the end.

But, the thing with possibilities, was that after the initial outbreak anything seemed possible. Not Clarke Griffin being alive, though. That was an unheard of possibility, but anything's possible in a world of the undead.


	2. Chapter 2

~Present Day~

Bellamy marked the sixth set of three hundred and sixty-five days upon the mural which he had been adding to every day that passes. It had been slightly longer than that since Clarke had died but it still stung like a fresh wound that was encountered yesterday. He had followed her advice, he found his sister, found a group and only trusted people who gave him utmost reason to. Most importantly, he moved on.

He found his sister after six months, she was the leader of a group of savages. For a while he stuck with them, stealing from survivors and killing innocent people in order to survive. It took him an additional six months to decide that his sister was irredeemable. She had changed into someone he couldn't recognise. He took into account her losses, including a boy Lincoln who had saved her life earlier in the apocalypse. Bellamy knew loss though, and it only turns you into a fiend if you let it. He was still fighting the temptation to let it. Still fighting the urge to give up, life was lonely and he missed Clarke more than ever.

~One year into the apocalypse~

"Don't worry, Bellamy. Octavia is stronger than you know. She can survive this," Clarke assured, her hair gleaming from the sun above, eyes softening whilst she strokes a soothing hand through his hair.

Clarke had learned how to give Bellamy hope when it seemed like it was beyond his reach. He had days like this, where he didn't know how to cope and she was always there to take some of the burden off his shoulders. He hadn't seen Octavia for over year now, he hadn't seen her since before the apocalypse and he spent his darkest days shadowed in a cloud of guilt and regret.

Clarke and Bellamy were out having dinner when the first warnings were broadcasted. The scene wasn't like in the movies, people weren't running and screaming for their lives, buildings didn't catch fire or anything ridiculous like that. The entire restaurant had stood still, eyes nonchalant as people silently questioned whether it was a hoax. Bellamy had instinctively grabbed Clarke's hand, leading her to his car. Before setting off he turned on the radio, all channels were repeating the emergency broadcast: "All citizens of the United States of America, this is your president speaking. We have been informed that a nuclear power plant failure has affected surrounding civilians. Everyone is urged to stay in their homes and wait for further announcements." By the time Bellamy got home Octavia was gone and the cell towers were down. He promised her he would always look after her ever since she was a little girl and now he wasn't even sure if she was alive.

"I don't think I could ever cope with losing you, Clarke," Bellamy sobbed, nuzzling his face into her lap.

"I'm not going anywhere, I promise."

With that, Clarke kissed the top of his head and wrapped her arms around his body. Clarke always managed to keep him centred, if it wasn't for her he probably would have stirred crazy by now. He was truly, unconditionally, irrevocably in love with her and the thought of losing her caused him more pain than any gunshot or knife wound ever could.

After leaving Octavia and her 'clan' he met two people called Monty and Harper. They were very similar to Clarke and Bellamy in that Monty was the emotionally driven one whereas Harper was the realist who let logic guide her. They helped him during an ambush, saving his life before he could get mauled by a zombie sneaking up on him. He could tell almost immediately that they were honest and kind people, but he followed Clarke's advice and kept his guard up. It took about a year for Bellamy to finally relax around them and by this point he genuinely trusted and believed in them.

After the year they met Raven who was severely injured when a building had collapsed in on her. They were scavenging for supplies when they heard nearby screams. It was Bellamy who cleared the debris and managed to carry her out. It was that point that he and the others decided that spending their lives running wasn't achieving anything. It was time to create a community, a place where life could prosper. The four of them spent the next two years gathering survivors and building in one of the least zombie affected areas. At present they had three hundred and forty-two people living within their walls. Each person contributed to making this way of life thrive. They had doctors, engineers, farmers and builders but most importantly they had hope.

Although things were thriving, Bellamy still counted the days since he had lost Clarke. It had been five years by the time their camp was up and running entirely. He hoped that wherever she was that she was proud of him. Proud of the smart decisions he's made. Understanding of the ones that were less so. Mostly he just hoped that there was a forgiving God who would let them spend eternity together when all of this was over.

His hope intensified when he had met Echo. She was the complete opposite to Clarke in every way, and she could never possibly replace her but she was a positive breath of fresh air and everything Bellamy needed to feel whole again. It was obvious that the apocalypse had taken its toll on her, she had made some brutal decisions, some that Bellamy could reason with, others that he had to block out. She was previously part of a group similar to Octavia's, full of fiends and savages with no morals. However, after the leader had been bitten, the group dispersed and went their separate ways and Echo found herself standing in front of the gates to 'Arkadia', asking for safe entry to which they allowed. The thing that made Echo and Bellamy work was that they both had skeletons in their closets, both had things to answer for, promises that were broken and amends to be made. Mostly, she was the only person that Bellamy could truly open up to about Clarke.

~six months prior to present day~

The day was very quiet, no zombie attacks, no deaths, no thefts. The day seemed oddly perfect. But a day without chaos also meant a whole day to think about Clarke with no distractions. Bellamy couldn't help but think about their old apartment, scattered in drawings and paintings that Clarke had made herself. They had planned to extend their living room and get a fish tank and maybe even a dog one day. Kids were on the horizon but their busy lives and strenuous jobs meant that they needed to wait a few years. Part of Bellamy wished they had sooner, just for the sake of having someone to hold onto that reminded him of her. He knew it was selfish, bringing a child up in this environment was selfish. But when it came to Clarke, he wanted to be selfish. He wanted to give up the whole life he had made in 'Arkadia' to go back and be with Clarke. God, he'd give some of his friends lives just to touch her. But that was selfish. Bellamy wondered where this all came from, Clarke had always accused him of thinking too much of others, and here he was now only thinking about himself. She really did keep him centred.

He thought about all of the stupid decisions he's made since Clarke has been gone. Killing Atom as an order from Octavia due to him stealing rations, telling Charlotte to fight her demons resulting in her killing one of the most innocent people he'd met in Octavia's clan. Shooting down ten men after accepting some rations of strange nuts and hallucinating that they were kidnapping Clarke. A tear escaped his eye when he heard a faint voice in the back of his head. "Three-hundred and forty two alive." It was Clarke's voice. Three-hundred and forty-two people, him having at least a small part to play in each and every one of their survivals. He knows that Clarke would be consoling him, reminding him of all the things he has achieved. Reminding him that we sometimes have to do the inexplicable in order to survive.

His thoughts were interrupted by the shuffling of his tent. He was expecting Harper or Raven, they always seemed to sense when he was upset, but he never really told them much. "Just thinking," he'd say. But when Echo entered it was different, almost as if he could feel that her loss was on a similar scale to his and he just let it all out to her.

"I just- Everyone around here has their family, their wives or mothers or children and I have nothing. I have no one. Sometime's I want to kill myself just so I could have the chance of possibly seeing her again. Isn't that fucked?" Bellamy finished, Echo listening intently.

"No. I don't think so at all," Echo said, sitting down next to him as she prepared herself to open up. "I lost my husband," she states flatly, not as a competition or as a way of invalidating his feelings, but just to reassure him that she understands completely.

He pulls up immediately looking straight at her.

"Shit, I'm so sorry, Echo."

She shrugs and offers a small smile.

"In a world like this loss is inevitable. Before this even happened it was inevitable. We just have to keep fighting and keep moving on because otherwise the past will haunt us and prohibit us from winning this goddamn war."

"How do you stay so hopeful?"

"Roan, my husband, always used to say, 'we must accept finite disappointment, but never lose infinite hope.' And ever since I have just decided to take each day as it comes, knowing one day I'll be back with him up there."

"You believe in God?"

"Not God so much as an afterlife. I believe we all get a chance to redeem our past sins and be back with the people we have loved and lost."

Bellamy stared at her, looking from her eyes to her lips before leaning in and closing the space between them. They continued messing around for the next month before deciding that they truly had feelings for each other and they didn't want their past to dictate their future, so for the next five months they lived as a couple, sharing a bed together, making decisions together. He still loved Clarke, but he knew that wherever she was, she was proud of him. He had defied all odds and created a well-ran society based on morals and logic. People were living, not just surviving.

~Present day~

The day had started like any other, the tight knit group had gotten up early, discussed development plans and then played some light hearted card games. Their main priority as of late was just keeping the camp in good spirits, having a high morale boosted efficiency and productivity, allowing the community to grow more and more each day. The camp was ever growing, now stretching from one side of the valley to the other. It consisted of a med bay, various fire pits, two storage houses; one for meat and one for herbs and materials, an array of tents for housing and even an indoor wooden shack created into a dining hall. With just over a year of work, it was impressive. In the next few months they hoped to find more survivors and expand, rebuilding the world from bottom to top. They also had scientists who spent their time doing experiments on the creatures, trying to figure out if there was a cure or vaccine to no avail. They'd keep trying, though.

Bellamy had made his way through the camp at about midday, striding towards the storage house to gather herbs for their main doctor, Jackson. It didn't take him long to realise that the unit was practically empty and he was going to need to organise an expedition to gather more materials. He consults his best hunter, Murphy, and only herbalist, Monty before saying goodbye to Echo and explaining the situation to Jackson. Expeditions usually lasted a day or two, sometimes longer depending on the supplies needed. Herbs were usually only a day trip but Bellamy figured that he may as well kill two birds with one stone and bring Murphy so they can hunt some meat also. It never occurred to Bellamy that he'd find a whole lot more than meat or herbs on his trip. It never occurred to him that he'd see a ghost standing in front of him, probably thinking the same question as him.

"Is this real?"


End file.
